An imaginary Number,when squared, offers a negative result.

You are watching: (1+i)(1-i)



Let"s try squaring some numbers to watch if we can acquire a negative result:

No luck! constantly positive, or zero.

It seems choose we cannot multiply a number by itself to obtain a an unfavorable answer ...


... Yet imagine that there is together a number (call it i for imaginary) that might do this:

Would it be useful, and also what might we carry out with it?

Well, by taking the square source of both political parties we obtain this:

Which way that ns is the answer come the square source of −1.

Which is actually an extremely useful due to the fact that ...

... By just accepting that i exists we deserve to solve thingsthat need the square root of a an unfavorable number.

Hey! that was interesting! The square root of −9 is merely the square root of +9, times i.

In general:

So long as we save that small "i" over there to remind united state that us stillneed to multiply by √−1 we space safe to proceed with ours solution!

Using i

Interesting! We supplied an imagine number (5i) and also ended up through a real solution (−25).

Imaginary numbers can assist us settle some equations:

Example: resolve x2 + 1 = 0

Using actual Numbers over there is no solution, however now us can settle it!

Subtract 1 native both sides:

Answer: x = −i or +i


(−i)2 + 1 = (−i)(−i) + 1 = +i2 + 1 = −1 + 1 = 0(+i)2 +1 = (+i)(+i) +1 = +i2 +1 = −1 + 1 = 0


Unit imaginary Number

The square root of minus one √(−1) is the "unit" imaginary Number, the indistinguishable of 1 for genuine Numbers.

In mathematics the symbol for√(−1) is i because that imaginary.

Can you take the square source of −1?Well i can!

But in electronic devices they use j (because "i" already way current, and the next letter after i is j).

Examples of imaginary Numbers

Imaginary Numbers space not "Imaginary"

Imaginary numbers were when thought to it is in impossible, and also so lock were called "Imaginary" (to make funny of them).

But then civilization researched them more and uncovered they were actually useful and also important due to the fact that they to fill a space in mathematics ... However the "imaginary" name has actually stuck.

And that is likewise how the name "Real Numbers" came around (real is no imaginary).

Imaginary Numbers are Useful


Complex Numbers

Imaginary numbers become most beneficial when merged with actual numbers come make facility numbers like 3+5i or 6−4i

Spectrum Analyzer


Those cool display screens you see when music is playing? Yep, complicated Numbers are used to calculate them! utilizing something dubbed "Fourier Transforms".

In fact numerous clever things deserve to be done v sound using facility Numbers, favor filtering the end sounds, hearing whispers in a crowd and also so on.

It is part of a subject dubbed "Signal Processing".



AC (Alternating Current) electricity changes in between positive and an unfavorable in a sine wave.

When we integrate two AC currents they might not match properly, and it deserve to be an extremely hard to number out the new current.

But using complex numbers provides it a lot simpler to do the calculations.

And the an outcome may have actually "Imaginary" current, however it deserve to still hurt you!


Mandelbrot Set

The beautiful Mandelbrot set (part of that is pictured here) is based on complex Numbers.

See more: ▷ Temporary Storage For Holding Data Until Ready Answers, Temporary Storage For Holding Data Until Ready

Quadratic Equation


The Quadratic Equation, i beg your pardon has plenty of uses,can offer results that include imaginary numbers

Also Science, Quantum mechanics and Relativity use complicated numbers.

Interesting Property

The Unit imagine Number, i, has an amazing property. That "cycles" v 4 various values every time we multiply:

1 × i= i
i × i= −1
−1 × i= −i
i × i= 1
Back to 1 again!

So we have this:

i = √−1i2 = −1i3 = −√−1i4 = +1
i5 = √−1i6 = −1...etc

Example What is i10 ?

i10= i4 × i4 × i2
= 1 × 1 × −1
= −1

And the leads us into another topic, the facility plane: